TY - JOUR

T1 - Effects of circulating extracellular microvesicles from spinal cord-injured adults on endothelial cell function

AU - Brewster, L Madden

AU - Coombs, Geoff B

AU - Garcia, Vinicius P

AU - Hijmans, Jamie G

AU - DeSouza, Noah M

AU - Stockelman, Kelly A

AU - Barak, Otto F

AU - Mijacika, Tanja

AU - Dujic, Zeljko

AU - Greiner, Jared J

AU - Phillips, Aaron A

AU - Ainslie, Philip N

AU - DeSouza, Christopher A

N1 - © 2020 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

PY - 2020/4/17

Y1 - 2020/4/17

N2 - People with spinal cord injury (SCI) have three- to four-fold greater risk of cardiovascular disease (CVD) compared with those without SCI. Although circulating extracellular microvesicles are key effectors of vascular health and disease, how their functional phenotype might be altered with SCI is unknown. The aim of the present study was to determine the effects of microvesicles isolated from SCI adults on endothelial cell inflammation and oxidative stress as well as endothelial nitric oxide (NO) synthase (eNOS) activation and tissue-type plasminogen activator (t-PA) expression. Eighteen young and middle-aged adults were studied: 10 uninjured (7M/3F; age: 39 ± 3 years) and 8 cervical level spinal cord injured (SCI; 7M/1F; 46 ± 4 years; cervical injury: C3: n=1; C5: n=4; C6: n=3). Circulating microvesicles were isolated, enumerated and collected from plasma by flow cytometry. Human umbilical vein endothelial cells (HUVECs) were cultured and treated with microvesicles from either the uninjured or SCI adults. Microvesicles from SCI adults did not affect cellular markers or mediators of inflammation and oxidative stress. However, microvesicles from the SCI adults significantly blunted eNOS activation, NO bioavailability and t-PA production. Intercellular expression of phosphorylated eNOS at Ser1177 and Thr495 sites, specifically, were ∼65% lower and ∼85% higher, respectively, in cells treated with microvesicles from SCI compared with uninjured adults. Decreased eNOS activity and NO production as well as impaired t-PA bioavailability renders the vascular endothelium highly susceptible to atherosclerosis and thrombosis. Thus, circulating microvesicles may contribute to the increased risk of vascular disease and thrombotic events associated with SCI.

AB - People with spinal cord injury (SCI) have three- to four-fold greater risk of cardiovascular disease (CVD) compared with those without SCI. Although circulating extracellular microvesicles are key effectors of vascular health and disease, how their functional phenotype might be altered with SCI is unknown. The aim of the present study was to determine the effects of microvesicles isolated from SCI adults on endothelial cell inflammation and oxidative stress as well as endothelial nitric oxide (NO) synthase (eNOS) activation and tissue-type plasminogen activator (t-PA) expression. Eighteen young and middle-aged adults were studied: 10 uninjured (7M/3F; age: 39 ± 3 years) and 8 cervical level spinal cord injured (SCI; 7M/1F; 46 ± 4 years; cervical injury: C3: n=1; C5: n=4; C6: n=3). Circulating microvesicles were isolated, enumerated and collected from plasma by flow cytometry. Human umbilical vein endothelial cells (HUVECs) were cultured and treated with microvesicles from either the uninjured or SCI adults. Microvesicles from SCI adults did not affect cellular markers or mediators of inflammation and oxidative stress. However, microvesicles from the SCI adults significantly blunted eNOS activation, NO bioavailability and t-PA production. Intercellular expression of phosphorylated eNOS at Ser1177 and Thr495 sites, specifically, were ∼65% lower and ∼85% higher, respectively, in cells treated with microvesicles from SCI compared with uninjured adults. Decreased eNOS activity and NO production as well as impaired t-PA bioavailability renders the vascular endothelium highly susceptible to atherosclerosis and thrombosis. Thus, circulating microvesicles may contribute to the increased risk of vascular disease and thrombotic events associated with SCI.

KW - Adult

KW - Case-Control Studies

KW - Cell-Derived Microparticles/metabolism

KW - Cells, Cultured

KW - Cytokines/metabolism

KW - Female

KW - Human Umbilical Vein Endothelial Cells/metabolism

KW - Humans

KW - Inflammation Mediators/metabolism

KW - Male

KW - Middle Aged

KW - Nitric Oxide/metabolism

KW - Nitric Oxide Synthase Type III/metabolism

KW - Oxidative Stress

KW - Phosphorylation

KW - Spinal Cord Injuries/blood

KW - Tissue Plasminogen Activator/metabolism

U2 - 10.1042/CS20200047

DO - 10.1042/CS20200047

M3 - Article

C2 - 32219341

VL - 134

SP - 777

EP - 789

JO - Clinical science (London, England : 1979)

JF - Clinical science (London, England : 1979)

SN - 0143-5221

IS - 7

ER -